Cbus chairman Steve Bracks says the industry super fund has had $1 billion in extra inflows since the banking royal commission, suggesting it is at the expense of retail funds.

Mr Bracks, the former Victorian premier who is also chairman of law firm Maurice Blackburn, said super funds should take an activist role in pushing companies on environmental and social issues, and said the Hayne royal commission's efforts at exposing misconduct in financial services have made Australians more engaged with their super.

Mr Bracks said the royal commission had highlighted the requirement of super trustees to act in members' interests and had been a "wake up call" for the sector.